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101.
Villalobos Virginia Suárez Jacqueline Estévez Jesús Novo Ernesto Bonilla Ernesto 《Neurochemical research》2001,26(10):1157-1161
In the present study the effects of chronic manganese (Mn) treatment on adenosine A2a receptor binding in mouse brain have been assessed. Male albino mice were divided in two groups: In the Mn-treated group, the animals were injected intraperitoneally (i.p.) with MnCl2 (5 mg/kg/day) five days per week during 9 weeks; in the control group, they were injected likewise with a saline solution. A significant decrease of the Kd without alteration of Bmax in the cerebellum and, an increase of the Kd and Bmax in hippocampus of mice treated with Mn were found. Also, an increase of Kd in frontal cortex was observed. The binding parameters in caudate nucleus, olfactory bulb and hypothalamus were not altered by Mn. A significant decrease in the adenosine concentration in caudate nucleus, olfactory bulb and hypothalamus, without significant changes in hippocampus, frontal cortex and cerebellum was also detected. These findings suggest that chronic administration of Mn could affect adenosine receptor function and turnover, depending on the brain region analyzed. 相似文献
102.
Medina-Leendertz S Valero N Chacín-Bonilla L Añez F Giraldoth D Arias J Espina G Díaz S Bonilla E 《Neurochemical research》2001,26(3):231-234
In mice infected with the Venezuelan equine encephalomyelitis (VEE) virus and exposed to high intensity light (2500 lux) with a 12 h light: 12 h dark photoperiod, a significant increase in the levels of melatonin in the olfactory bulb was observed. The significance of these findings deserves further studies to understand the mechanisms involved in this effect since the olfactory bulbs have been proposed as first portal for VEE virus entry into the CNS. The increase in melatonin content could represent one of the mechanisms of defense against the viral attack. 相似文献
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In the cerebellum, infusion of NMDA (200 microM) for 20 min evoked a marked (200%) increase of extracellular cyclic GMP (cGMP) levels. The selective GABA(A) receptor agonist muscimol (0.01-100 microM) was able to counteract the NMDA effect with an EC(50) of 0.65 microM; the inhibitory effect of muscimol (10 microM) was prevented by bicuculline (50 microM). Diazepam (10 microM) significantly potentiated the muscimol (1 microM) inhibition; furthermore, when coinfused with 0.1 microM muscimol (a concentration not affecting, on its own, the cGMP response to NMDA), diazepam (10 microM) reduced the NMDA effect. Similar results were obtained with zolpidem (0.1-1 microM). Finally, local infusion of the benzodiazepine site antagonist flumazenil (10 microM), together with muscimol and diazepam, almost completely restored the effect of NMDA on extracellular cGMP levels. It is concluded that GABA(A) receptors potently control the NMDA/nitric oxide/cGMP pathway in the cerebellum in vivo. In terms of the alpha subunit composition, we can deduce that the cerebellar GABA(A) receptor does not contain alpha(6) or beta(4) subunits because it is diazepam-sensitive. Moreover, the observation that zolpidem is active at a rather low concentration, in combination with localization studies present in the literature, tend to exclude the presence of alpha(5) subunits in the receptor composition and suggest the involvement of an alpha(1) subunit. 相似文献
105.
Spatial and Temporal Deposition of Adhesive Extracellular Polysaccharide Capsule and Fimbriae by Hyphomonas Strain MHS-3
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Hyphomonas strain MHS-3, a member of a genus of primary colonizers of surfaces immersed in marine water, synthesizes two structures that mediate adhesion to solid substrata, namely, capsular exopolysaccharide and fimbriae. Specific stains, gold-labelled lectins, and monoclonal antibodies, along with transmission electron microscopy of synchronized populations, revealed that both structures are polarly and temporally expressed. The timed synthesis and placement of the fimbriae and capsule correlated with the timing and locus of MHS-3 adhesion. 相似文献
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108.
Nitrogen distribution and leaf area indices in relation to photosynthetic nitrogen use efficiency in savanna grasses 总被引:3,自引:0,他引:3
Leaf photosynthetic characteristics, distribution patterns of nitrogen content per unit leaf area (nL) and leaf area production per unit nLwere measured in natural stands of a C4 grass (Hyparrhenia rufa) from the seasonal savannas and of a C4grass (Paspalum fasciculatum) and two C3grasses (Leersia hexandra and Hymenachne amplexicaulis) from the flooded savannas in central Venezuela. Daily rates of canopy photosynthesis (PcD) as well as the optimal leaf area production per unit nLat which PcDfor a given total amount of nitrogen in the canopy (i.e., canopy-PNUE) is maximized were also calculated. The C3and C4species from the flooded savannas had similar light saturated rates of photosynthesis per unit nL(i.e. leaf-PNUE) and similar canopy-PNUEs which was in strong contrast with previous studies. Especially H. rufa but also L. hexandra and H. amplexicaulis had leaf- and canopy-PNUEs which were considerably higher than the values calculated for most other species with the same photosynthetic pathway (i.e., C3or C4). In contrast to previous studies, differences in the light gradient in the canopy between stands only partially explained differences in N distribution. Measured leaf area indices were greater and the average nL values were consequently smaller than the calculated optima. There was, however, a very strong linear correlation between the optimal and actual average nLindicating that even though the model overestimated average nL, it did predict the differences in leaf area production per unit nitrogen – the inverse average nL– very well. This result strongly indicates that leaf area production per unit of leaf nitrogen increases with leaf-PNUE and decreases with the extinction coefficient for light. Grass species from seasonal savannas have extremely high leaf-PNUEs and thus optimally produce large amounts of leaf area per unit nL. This helps explain how stands of these species may have high leaf area indices and achieve high photosynthetic productivity despite the very low nutrient availability at which they grow. 相似文献
109.
Paul E. Rolan Gilmore O’Neill Eve Versage Jitesh Rana Yongqiang Tang Gerald Galluppi Ernesto Aycardi 《PloS one》2015,10(5)
ObjectiveTo evaluate the safety, tolerability, and pharmacokinetics of single doses of BG00010 (neublastin, artemin, enovin) in subjects with unilateral sciatica.MethodsThis was a single-center, blinded, placebo-controlled, randomized Phase 1 sequential-cohort, dose-escalation study (ClinicalTrials.gov identifier ; funded by Biogen Idec). Adults with unilateral sciatica were enrolled at The Royal Adelaide Hospital, Australia. Four subjects were assigned to each of eleven cohorts (intravenous BG00010 0.3, 1, 3, 10, 25, 50, 100, 200, 400, or 800 μg/kg, or subcutaneous BG00010 50 μg/kg) and were randomized 3:1 to receive a single dose of BG00010 or placebo. The primary safety and tolerability assessments were: adverse events; clinical laboratory parameters and vital signs; pain as measured by a Likert rating scale; intra-epidermal nerve fiber density; and longitudinal assessment of quantitative sensory test parameters. Blood, serum, and plasma samples were collected for pharmacokinetic and pharmacodynamic assessments. Subjects were blinded to treatment assignment throughout the study. The investigator was blinded to treatment assignment until the Data Safety Review Committee review of unblinded data, which occurred after day 28.ResultsBeyond the planned enrollment of 44 subjects, four additional subjects were enrolled into to the intravenous BG00010 200 μg/kg cohort after one original subject experienced mild generalized pruritus. Therefore, a total of 48 subjects were enrolled between August 2009 and December 2011; all were included in the safety analyses. BG00010 was generally well tolerated: in primary analyses, the most common treatment-emergent adverse events were changes in temperature perception, pruritus, rash, or headache; no trends were observed in clinical laboratory parameters, vital signs, intra-epidermal nerve fiber density, or quantitative sensory testing. BG00010 was not associated with any clear, dose-dependent trends in Likert pain scores. BG00010 was rapidly distributed, with a prolonged terminal elimination phase.ConclusionsThese data support the development of BG00010 for the treatment of neuropathic pain. NCT00961766
Trial Registration
ClinicalTrials.gov NCT00961766相似文献110.
Ernesto Maddaloni Nader Lessan Alia Al Tikriti Raffaella Buzzetti Paolo Pozzilli Maha T. Barakat 《PloS one》2015,10(8)